Arrangement in internal-combustion engines, particularly for rock drills and the like



Aug. 10, 1954 G. A. BERGMAN 2,685,867

ARRANGEMENT IN INTERNAL-COMBUSTION ENGINES, PARTICULARLY v FOR ROCK DRILLS AND THE LIKE Filed March 25, 1951 5 Sheets-Sheet 1 IN V EN TOR:

Aug. 10, 1954 BERGMAN 2,685,867

ARRANGEMENT IN INTERNAL-COMBUSTION ENGINES, PARTICULARLY FOR ROCK DRILLS AND THE LIKE Filed March 25, 1951 3 Sheets-Sheet 2 IN VEN TOR:

Aug. 10, 1954- e. A. BERGMAN 2,685,867

ARRANGEMENT IN INTERNAL-COMBUSTION ENGINES, PARTICULARLY FOR ROCK DRILLS AND THE LIKE Filed March 25, 1951 s Sheets-Sheet 3 92E 140 58 E 95 90 Y fg 94 a5 I02 120 04 I32 i I 4 6 IN V EN TOR:

' clumsy. and difiicultly -manageab1e.

Patented Aug. 10, 1954 UNITED STATES PATENT OFFICE ARRANGEMENT IN INTERNAL-COMBUSTION ENGINES, PARTICULARLY FOR ROCK DRILLS AND THE LIKE Gustav Albert Bergman, Danderyd, Sweden Application March 23, 1951, Serial No. 217,143

Claims priority,application Sweden April 29, 1950 8 Claims. 1

Rock-drills and the like operated by an internal combustion engine combined with other machincry and used as hand tools require a compact structure in order that they do not become It is desirable, also, that they operate satisfactorily independently of their position, inasmuch as different works require different directions of the tool, for instance vertically downwards, horizontally, or

" even vertically upwards The present invention constitutes a link in the endeavours to comply with these requirements. The invention is especially intended for internal combustion engines of rock-drills, but may also be applied'in internal combustion engines for the operation of other machines for similar methods of use,"such as chiselling machines, rivet hammers and the like.

An object of theinvention is to provide an internal combustion engine for the operation of rock drilling machines which can be easily started during'various conditions. l

A further object of the invention isto obtain a rock drilling machine operated by an internal combustion engine and ableto operate-in .difierent positions, i. e. not only withavertica-l axis but also in other directions;

drill 'A still further object of the invention is to provide a crank housing for internal combustion engines being of a compact structure; and enclosingwithin the walls of the crank housing all the most importantelements appertaining: to the engine and'also having its walls formed with air ducts and fuel passages.

Still further objects of the invention will appear from the following description of an embodiment of the invention, reference being had to the accompanying drawings which represent the upper part of a machine having an internal combustion'engine according to the invention. Fig. 1 shows a. vertical elevation in a plane perpendicular to the crankshaft of the motor, this elevation being shown partly in section on line li of Fig. 2, Fig. 2 is an elevation on a plane perpendicularto the former section and shown partly 'in section here too, the section according to Fig. 2 extending along the broken .line IIII in Fig. 1. Fig. 3 is a central section ona somewhat smaller scale along the crank shaft, and

Fig.4 shows a detail'on a larger scale.

In the embodiment shown, the crank housing of the engine consists, broadly, of a single main part H], which may preferably be moulded from light-metal, and this main part has the carburetter, air cleaning filters, the valves, the magneto,

. spindle the fuel tank and the requisite passages for air, fuel and the fuel-air-mixture arranged or formed therein.

The crank housing is provided at the top with a pocket l2 having a filter housing [4 projecting into the same from above, said filter housing being so much smaller than the pocket that an intervening space [6 is formed between the walls of the pocket and those of the filter housing, said intervening space extending preferably round the filter housing and forming a passage for air. The filter housing is provided at the top with an inlet socket l8 having a plurality of lateral openings 20 therein, whence air has access to the intervening space It through an obliquely and downwardly directed passage 22. Rotatably fitted into the socket I8 is a valve member 24 in the form of a cover having a circumferentially extending flange with apertures 26, which by a turning movement of the cover may be adjusted more or less in register with the openings 20. The valve member 24 is retained by means of a 28 extending centrally downwards through the upper wall of the filter housing and being threaded here to receive a nut 29 and a spring washer 31, whereby the spindle and the cover are urged resiliently in a downward direction. The valve member 24 forms together with the air supply may be cut oif more or less, when the engine is to be started. The filter housing contains a filter body 30 above its lower open end and above this filter body a wire net 32, by

means of which the air is filtered when passing through the filter housing. Atthe top, the filter housing is provided with an opening 34 leading to an outlet passage 36 in a projection 38 extending laterally outwards beyond the upper side ofthe wall of the crank housing. This projection is provided on the lower side thereof with an aperture 40 opening into an induction channel or duct portion 42 extending in a continuation of the crank housin wall.

, The passage through the aperture 40 is controlled by a self-closing valve 44 adapted to open at the creation of a pressure below atmospheric in the channel or duct portion 42. A self-closing valve 46 is also arranged in the channel portion 42 nearer to the engine side. The 'valves are constructed so that in the operation of the'eng'ine they renderpossible the maintenance of a pressure below atmospheric in the induction channel portion 42 therebetwe'en. They may be made with particular advantage as shown in the drawing with a valve body in the form of a 'leaf'spring against damages bent stifi strip or the like 50, which may be retained with the same screws 52 as the leaf spring. The two valves 44, 46 are preferably constructed in the manner described, but if desired one of them may be replaced by a self-closing valve of a different construction, for instance in the form of a spring-loaded flap valve having a pivotally mounted rigid valve flap. In certain cases both valves may be made in this or in.

some other way.

The valve 4-4, which is arranged on the lateral projection of the filter housing, remains with the filter housing when the latter is removed from the pocket 52, and is therefore readily accessible for repairs or an exchange. The valve 46 may be easily attended to in a similar manner, the same being secured to the inside of a plate 54 fitted into a recess in the wall of the crank housing. The air induction channel extends through this plate as, and the inside of the plate or a ring from cast iron or the like secured in the plate, for instance by being moulded into the same, forms a valve seat having the leaf spring 48 of the valve 46 hearing thereon. The air induction channel continues behind the valve 45 directly into the crank housing chamber 56.

At the top, the crank housing encloses a fuel tank or fuel space 58, the walls of which are formed by upwardly directed extensions of the crank housing wall. Extending in the wall of the fuel chamber is a fuel supply passage 69, which may be formed by the moulding of a pipe 62, for instance from copper, into said wall. The fuel passage 59 opens at a narrow point of the air induction channel 4 2 through a nozzle 64, which is displaceably fitted into a recess in the channel wall, and is kept pressed into said recess by means of a spring 66. Between an abutment 55 in the recess and a flange 6] on the nozzle there is inserted a ring 69, Fig.4, consisting of a resilient material such as rubber. A valve needle 68 adapted to be screwed in and prefer- I in accordance with varying conditions relative to the temperature and the moisture percentage of the external air. The valve needle carries a handle I! on the outer end thereof, and provided between this handle and the crank housing wall is a spring 13.. On account of the packing ring 69, the valve needle and the nozzle are protected should the valve needle be screwed in so far as to find a support on the nozz e.

A throttle member '76 is arranged in an enlarged portion of the induction channel 42 immediately behind the nozzle 64. This throttle member may be operated by means of a control device 12, which may be of any arbitrary suitable construction. 7

The fuel supply passage 60 has its inlet end ing 14 and formed at the outer end thereof into a head provided with a spanner grip. A packing ring 82 tightens between this head 80 and the wall of the fuel chamber when the member 18 is tightened up. Provided in the wall of the sleeve is an aperture 84, tl1rough which the fuel on having passed through the strainer net 16 may flow out into the opening M, whence it finds its way into the passage 60.

The strainer is located on or in the propinquity of. the lowermost point of the fuel chamber, when the machine is standing with the axis of the engine piston directed vertically and with the tool directed downwardly.

The crank housing and the fuel tank may be cast integral from light-metal, such as the aluminum-magnesiumalloys sold commercially under the trade-mark Elektron, which casting, in "the construction shown, is also formed with spaces for fans for the cooling of the engine and the magneto for the ignition system of the engine The left end of the crank shaft 86 as viewed in Fig. 3 has arranged thereon a fan wheel 88 :in a fan housing 90, the peripheral wall 92 of which forms a continuation of the crank housing wall. The fan housing is covered laterally by a head plate 94 having an intake 96 for the cooling In 'a'similar manner, the right-hand portion of Fig. 3 shows a peripheral wall 98 formed as a continuation :of the crank housing wall for a fan housing Hi0 having a head plate I02 with air intakes I04 for a fan wheel I06 on the right-hand end of the crank shaft. The fan wheel N16 is formed as a fly-wheel for the engine, and acting as .a gyrating mass there is also a ring I 08 of'permanent magnets and cast-iron holders for the same. Between the fly wheel and the crank housing chamber, the crank housing is provided with a lateral opening, which is closed by means of a crank housing cover H0 provided with an outwardly projecting axial flange H2, which together with an inwardly extending axial flange H4 on the fly-wheel forms a space enclosing the magneto. Thus the armature H6 of the magneto with its coil I [8, as well as a condenser I20 pertaining to the magneto, are secured on the crank housing cover lit. The magneto is made accessible by the removal of the head plate I02 and the fanor fly-wheel H16, and upon removal'of the crank wheel cover I if the crank shaft 86 can also be readily dismounted.

Fig. 3' also shows the connecting rod N2, the engine piston i124, the engine cylinder I26 and the impact plunger I21 movable in the lower part of the engine cylinder, said plunger being intended with its plunger [28 to actuate the boring bit (not shown) of the machine. The motor piston I24, which is hollow and open upwardly toward the crank housing chamber, is provided with a lateral opening l30, which in cooperation with suitably arranged inlet ports 532 controls the scavenging of the motor cylinder and the blowing'of the fuel-air-mixture into the same in a manner known from two-stroke cycle engines, during the reciprocating movement of the engine piston. In dependence on the position of the piston, an outlet port 534 permits the escape of the exhaust gases to an exhaust pipe I36, which may be arranged within a protecting jacket 138 surrounding the motor cylinder underneath the fan wheel 88, so that the cooling air coming from the latter and flowing ahead in the intervening space between the jacket I38 and the cylinder is forced to flow in contact with the exhaust pipe 1'36 and. also to cool the lattersimultaneously with the cylinder. As shown in Figs. 1 and 3, a passage I40 for cooling air may extend between the crank housing chamber 55 and the fuel chamber 58, one end of said passage communicating with the air filter pocket It and the other end opening into the jacket I38. The top portion of Fig. 3 shows a transversely extending rod I42 provided on the projecting ends thereof with handles I44, I45, by means of which the labourer holds the machine during the work. A spark plug is designated by I48.

With respect to the induction of fuel and air, the mode of operation of the machine is broadly as follows:

In the drawing (Figs. 1 and 3), the engine piston l 24 is shown in its extreme position in the engine cylinder 126. When the piston moves inwardly in the latter, a pressure below atmospheric is created in the crank housing chamber 56, whereby the leaf-spring valves 44 and 46 are caused to open. At the same time, the sucking effect manifests itself in the induction channel 42. Air is thus sucked in through the chokevalve, the air cleaning filter, and the valve 44, while fuel is at the same time sucked up into the induction channel through the strainer 16, the sleeve member 18, the openings 84, the opening 14, the passage 50, and the nozzle 64. Air and fuel are mixed in the induction channel, and the fuel is gasified on its Way through the valve 46 to the crank housing chamber 56. When the piston turns on having reached its inner dead center position, the fuel-air-mixture sucked into the crank housing chamber will be compressed by the fact that the spring valve 46 closes immediately. When the piston then commences to approach its outer dead center position anew, the crank housing chamber is brought into communication with the cylinder space through the lateral opening I30 of the engine piston and the port I32, the compressed 'fuel-air-mixture then rushing into the cylinder space to wash out any combustion gases present therein and filling the cylinder space.

The valves 44, 46 close between them that portion of the induction channel into which the fuel nozzle 64 opens. In this portion remains a certain pressure below atmospheric even upon the closure of the valves, said pressure below atmospheric being equalized through the induction of fuel and any leakage in the valves. Gasified fuel is thus always available in the induction channel, which makes the engine easy to start.

The invention is not limited to the constructive details shown, which are only intended to serve as elucidating examples.

What I claim is:

1. In an internal combustion engine of the two cycle type, a crank housing having a crank housing chamber and an air duct connecting the crank housing chamber with the atmosphere, the crank housing further having a fuel chamber, a manually adjustable choke valve and an air filter at the inlet end of said air duct, a pair of selfclosing leaf spring valves in series arrangement in said air duct between said choke valve and the crank case chamber, and a fuel passageway extending from said fuel chamber to a port opening into said air duct at a point located between said leaf-spring valves, both of said leaf-spring valves being adapted to open at air flow toward the 6 crank housing chamber and to close upon air fiow in the opposite direction.

2. A crank housing for internal combustion engines for the operation of rock drilling machines, said housing being formed with a crank chamber and a fuel space and having in its wall an air duct leading from the atmosphere to said crank chamber, a pair of self-controlled air valves in said air duct, and a fuel passage extending from the bottom of the fuel space and opening into the air duct at a point located between said valves.

3. A crank housing as claimed in claim 2 and further having the fuel supply passage formed by a tube moulded into the wall of the crank housing.

4. In an internal combustion engine for the operation of a rock drilling machine, a crank housing enclosing a crank chamber and a fuel space and having its wall formed with an air duct and a fuel passage, the air duct connecting the atmosphere with the crank chamber and the fuel passage extending from the bottom of the fuel space to a port at a point in the air duct, 2. pair of leaf spring valves operated by the suction generated by the engine to open toward the crank chamber, said valves being in said air duct at opposite sides of said port, whereby said valves when closed trap a fuel-air mixture in a portion of said air duct.

5. An internal combustion engine as claimed in claim 4, having a strainer mounted in an opening in the wall of the fuel chamber in the passage for the fuel from said fuel chamber to the air duct.

6. In an internal combustion engine as claimed in claim 4, a strainer mounted in an opening in the wall of the fuel chamber, said opening communicating with the fuel chamber and with the fuel passage, a sleeve-shaped member screwed into said wall opening and having its inner end formed as a seat for said strainer and its outer end formed to a head tightening at the outer wall of the crank housing.

7. In an internal combustion engine as claimed in claim 4, a seat for one of said leaf spring valves, said seat comprising a cast-iron ring, and a bent strip mounted at the back of the leaf spring to form an abutment for restriction of the opening movement of the spring.

8. An internal combustion engine as claimed in claim 4 and further comprising a fuel nozzle mounted at said port, said nozzle being axially displaceable, a resilient ring supporting said nozale and a valve needle for cooperation with the nozzle, said ring being adapted to be compressed on setting the needle against the nozzle.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,195,070 Nelson Aug. 15, 1916 1,647,554 Trapnell Nov. 1, 1927 2,121,706 Little June 21, 1938 2,172,147 Smith Sept. 5, 1939 2,480,879 Rice, Jr Sept. 6, 1949 2,501,744 Seligmann Mar. 28, 1950 2,506,306 Mantle May 2, 1950 2,549,478 Kiekhaefer Apr. 17, 1951 

